In a desolate, snow-covered future where water is incredibly scarce, humanity clings to life around massive Orbital Trees. The story follows Kaina, a young man living atop one of these trees, in a realm called the Canopy.
His isolated existence is disrupted when Ririha, a princess from the surface world, arrives seeking a legendary sage who can solve the water crisis.
Unable to find the sage and stranded, Ririha enlists Kaina's help to return home. This journey thrusts Kaina into the harsh realities of the surface, exposing him to war, political conflict, and the struggles of a dying world.
As Kaina escorts the princess, he begins to understand the desperate situation humanity faces and the perilous road ahead.